全文获取类型
收费全文 | 1824篇 |
免费 | 50篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 20篇 |
化学工业 | 318篇 |
金属工艺 | 50篇 |
机械仪表 | 93篇 |
建筑科学 | 51篇 |
矿业工程 | 4篇 |
能源动力 | 70篇 |
轻工业 | 71篇 |
水利工程 | 6篇 |
石油天然气 | 9篇 |
无线电 | 227篇 |
一般工业技术 | 432篇 |
冶金工业 | 243篇 |
原子能技术 | 60篇 |
自动化技术 | 230篇 |
出版年
2023年 | 22篇 |
2022年 | 45篇 |
2021年 | 51篇 |
2020年 | 41篇 |
2019年 | 40篇 |
2018年 | 38篇 |
2017年 | 35篇 |
2016年 | 42篇 |
2015年 | 26篇 |
2014年 | 57篇 |
2013年 | 113篇 |
2012年 | 67篇 |
2011年 | 94篇 |
2010年 | 94篇 |
2009年 | 79篇 |
2008年 | 80篇 |
2007年 | 63篇 |
2006年 | 64篇 |
2005年 | 35篇 |
2004年 | 39篇 |
2003年 | 43篇 |
2002年 | 34篇 |
2001年 | 29篇 |
2000年 | 30篇 |
1999年 | 22篇 |
1998年 | 39篇 |
1997年 | 36篇 |
1996年 | 32篇 |
1995年 | 32篇 |
1994年 | 29篇 |
1993年 | 25篇 |
1992年 | 22篇 |
1991年 | 30篇 |
1990年 | 31篇 |
1989年 | 19篇 |
1988年 | 22篇 |
1987年 | 21篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 27篇 |
1983年 | 21篇 |
1982年 | 25篇 |
1981年 | 21篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 11篇 |
1977年 | 19篇 |
1976年 | 30篇 |
1975年 | 6篇 |
1973年 | 9篇 |
排序方式: 共有1884条查询结果,搜索用时 15 毫秒
1.
Bhattacharya Subhayan Sinha Sankhamita Roy Sarbani Gupta Amarnath 《The Journal of supercomputing》2020,76(12):9882-9900
The Journal of Supercomputing - Currently, all online social networks (OSNs) are considered to follow a power-law distribution. In this paper, the degree distribution for multiple OSNs has been... 相似文献
2.
3.
V. Sinha M. J. Mills J. C. Williams 《Metallurgical and Materials Transactions A》2006,37(6):2015-2026
A faceted initiation site is observed in Ti-6242 alloy for both the cyclic and static-loading test conditions. In this experimental
study, the crystallographic orientation of the facets has been determined using the electron backscattered diffraction (EBSD)
technique in conjunction with the quantitative tilt fractography in a scanning electron microscope (SEM). Quantitative tilt
fractography analysis has been used to determine the spatial orientation of fracture facets. The results indicate that the
normal-fatigue (no-dwell) fracture facets are oriented at ∼5 deg with respect to the basal plane; the dwell-fatigue fracture
facets are oriented at ∼10 to 15 deg with respect to the basal plane and the static-loading fracture facets are oriented at
∼20 deg with respect to the basal plane. These crystallographic orientation determinations of the fracture facets at the crack-initiation
site can be used to obtain an idea about the type of loading that produced them. 相似文献
4.
5.
6.
Family nursing, always a component of nursing, has been recently receiving increased attention through publications, educational programs, clinical practice settings and family nursing research. Nurses are in the best position to assist families experiencing the illness of a loved one, but often lack the skills and confidence necessary to assist with the psychosocial needs. The purpose of this paper is to describe the development and implementation of a family nursing program within a large, tertiary care facility. The program's evaluation is ongoing but early outcomes indicate that day-to-day nursing practice has been positively influenced and improved job satisfaction may result. 相似文献
7.
8.
9.
M. K. Karthikeyan R. K. Gupta V. Rajesh B. R. Ghosh P. P. Sinha 《Journal of Failure Analysis and Prevention》2007,7(6):429-433
17-4 PH stainless steel is used as internal drive shaft material in liquid engine pumps. One of the drive shafts failed during
operation. The shaft pieces were in contact for short duration after failure, which has resulted in abrasion of fractured
surfaces. Samples from the location of failure were taken, and investigation of the failure was carried out using optical
and scanning electron microscopy. The microstructural analysis of the material and fractographic analysis of the fractured
surface show that the failure was caused by excessive torsion. 相似文献
10.
New modulation formats are presented that increase the transmission rate over that of conventional systems, without degrading the bit error rate (BER) and with minimal bandwidth variation. A time-varying function called an "extra phase variation function" (EPVF) is added to the discrete phase of conventional modulation formats such as M-PSK and QAM to transmit additional data bits. A receiver configuration is presented that allows the decoding of information represented by the discrete and extra phases. It is shown that in an additive white Gaussian noise (AWGN) channel, the BER performance of the bits carried by the discrete phase and the extra phase in the modified format improves over the BER of conventional modulation formats. 相似文献